1. Field of the Invention
The present invention relates to a method and device for estimating DOA, and more particularly to a method and a device of vehicle radar for estimating DOA.
2. Description of the Prior Art
Nowadays, radar has been widely applied to the field of tracking or searching targets. In order to increase accuracy of target tracking, detection errors of radar needs to be reduced. To achieve this goal, industrial and academic circles propose different solutions to improve the accuracy of radar detection.
There are many DOA methods proposed such as conventional digital beamforming, Capon's beamforming and Multiple Signal Classification (MUSIC) algorithm. In general, the Capon algorithm uses Minimum Variance Distortion Less Response (MVDR) to estimate DOA of the reflected signals. The MUSIC algorithm utilizes an antenna array. The basic concept of MUSIC algorithm is: the autocorrelation matrix of the reflected signal is decomposed to signal sub-space and noise sub-space, and it uses the feature of orthogonality between these two sub-spaces to estimate the DOA of the reflected signal.
However, the known Capon's beamforming and conventional digital beamforming algorithm needs more antennas to achieve better resolution in detecting more targets. In addition, the MUSIC algorithm can distinguish many targets with high angular resolution, but the number of the targets detected is limited due to the characteristics of the methodology. As a result, more antennas need to be applied for detecting more targets under this method. Therefore, these above-mentioned algorithms need to be improved in practical.